La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Florida Scrub-jays eject foreign eggs added to their nests
Auteurs :	T. L. Fleischer, Auteur ; G. E. Woolfenden, Auteur
Type de document :	Article
Dans :	Journal of Field Ornithology (75(1) WIN 2004)
Article en page(s) :	49-50
Langues:	Anglais
Résumé :	Brown-headed Cowbirds (Molothrus ater), and to a lesser extent Shiny Cowbirds (M bonariensis), have expanded their breeding ranges to include that of the Florida Scrub-Jay (Aphelocoma coerulescens). We added the eggs of seven bird species to Florida Scrub-Jay nests to determine if scrub-jays eject foreign eggs. Most eggs were ejected within 1 d of addition, probably by grasp-ejection. Ejection of foreign eggs by Florida Scrub-jays suggests that cowbirds, should they begin to parasitize scrub-jays, would waste their reproductive effort. Fossil evidence suggests that Florida Scrub-jays may be former cowbird hosts that have sustained the ability to eject.

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